Wednesday, 01 February 2012

A Map Mystery

By Eleonore Dixon-Roche

Figure 1: Map from December 6th 1920. The journal entry describes the river as “winding as ever” which can be seen in the map. (From Joseph Francis Rock, field notes, 1920-1929. Folder 3: Rock, J.F.: Siam, Burma, Assam, 1920-1921.)

I started working on an assignment for the Field Book Project in September 2011 as an intern cataloguing maps for various departments at the Smithsonian National Museum of Natural History. I looked at one of Botanist Joseph Rock’s (see also http://goo.gl/ay2O1) extensive journeys throughout Asia that he completed during the early 1900s. For a brief portion of those travels in 1921, Rock created hand-drawn maps with corresponding journal entries in a manuscript covering his travels of 1921-1922. We knew from a general collection description that he traveled through Burma, Thailand, and Siam. His maps also provided enough detail to establish the general direction of travel and discern some distinctive geological landmarks. Pinpointing an exact location and specific route, however, was fraught with issues.

Whilst the map did include place names of where Rock and his native guides passed through, each place name was written phonetically, with multiple spellings for the same location being used throughout his journal. Disambiguating these place names was especially difficult because there was no mention of what country they were in, let alone detailed accounts of the location.

To complicate matters, the majority of these locations were small villages that are not registered in most indexes or Google Earth. In addition, the place name could be several words, and the point at which the series of letters were split into words seemed arbitrary at times. Some place names were rather commonly used throughout the region for different locations and therefore not a good indicator of a unique location. The river seemed to disappear at certain points, and it did not seem likely that natural events would have caused this. Lastly, due to the high density of rapids in certain areas it was rather difficult to pin point exactly which river he went down. As the rapids were mentioned multiple times as a reference to his location this could have been key to narrowing down his route further (Figure 2). As the scale was not perfect, the maps also could not be used for calculating accurate distances or for actual variations in river width.

Figure 2: An excerpt from page 7 of Rock's journal, one of the many references to the high density of rapids. (Rock, J.F.: Siam, Burma, Assam, 1920-1921)

Deciphering Rock’s route was daunting at first, but there were in fact some great clues and rather simple solutions to many of the challenges. Though the journal and maps did not correlate exactly, I was able to work backwards from the route described in his journal, to find the general direction he had come from. The map shown in Figure 1, for example, has the corresponding journal entry for December 6: "The banks of the river are now flat and fringed by trees and Bamboo; and as is as winding as ever."

I was also able to narrow down countries he was passing through whilst disambiguating and the mention of a river’s name in both Thai and Burmese. Discounting some inaccuracies of scale, I focused on the distinctive forks and bends Rock marked along the river on his maps to plot them in Google Earth (Figurea 3a and 3b).

Figure 3b. Bends in Rock’s maps lined up with a contemporary satellite view of a river using Google Earth.

Along with the sporadic descriptions from the journal of the water’s speed, the river’s width, and the occasional island, it was possible to begin confidently marking some points along my virtual route on Google Earth. In the more ambiguous areas, I used what little information the maps conveyed on the mountain ranges to ascertain the general direction he could have traveled using waterways. After working out the general direction in which he was traveling, I looked at the place names on Google Earth and correlated any that sounded similar. This method only worked for a few locations. Next, I made note of every place name that was mentioned in both the journal and the maps. I then sorted through the lists and made note of those that sounded similar. Using various websites listing all Thai cities and villages, I pinned them all on Google Earth. Some were immediately discounted due to their location, but once all the pins were in place, a path became unequivocally clear.

The remaining ambiguous routes were described as narrow rivers with fast moving water, leading to an assumption that they were rapids. This region was full of rapids in areas less than approximately a square mile. For these sections, it was impossible to be accurate beyond a general area.

Even though Rock’s maps presented serious challenges in trying to line up with contemporary maps, it was interesting to observe how the accuracy of the maps increased along his journey. This may be due to the fact that later locations had more distinctive landmarks, which can be seen in pages 8 and 9. It is unlikely that his cartography skills would have improved substantially, however his observation skills may have.

The most intriguing part of this project was where Rock's map was almost logically aligned with the features shown on Google Earth, but one section remained where the river in the satellite images seemed to disappear into a rather large lake that was not marked on Rock's map. The discrepancy took up a significant portion of the route and required closer examination. Upon looking at it, Rusty Russell, the Collections Manager in the Dept of Botany, immediately knew to zoom in as far as possible on the Google Earth map. And lo and behold, there was now a dam, which had drastically altered the landscape and waterways since Rock's travels (Figure 4).

To view the full course of Rock's journey that was plotted in Google Earth, you can Download JosephRockJourney or click on the map below to view in Google Maps. Enjoy!

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Hi Keith,

We were all very impressed with the detective work as well and are glad to hear that you enjoyed this post. While we don't currently have any other map mysteries scheduled for the blog, we'll gladly share them here when they come to our attention. Thanks for reading and commenting!

The Field Book Project is an initiative to increase accessibility to field book content that documents natural history. Through ongoing partnerships within and beyond the Smithsonian Institution, the Project is making field books easier to find and available in a digital format for current research, as well as inspiring new ways of utilizing these rich information resources.